1. Field of the Invention
This invention relates to an apparatus for measuring the frequency deviation between a reference sound and a sound to be measured for the purpose of tuning a musical instrument and the like. More specifically, the present invention relates to a digital tuning apparatus which directly expresses the frequency deviation in terms of a cent value.
2. Prior Art
Various tuning apparatus have heretofore been proposed. Among them is a relatively new type which extracts a fundamental wave from a signal to be tuned by use of filters, etc., and obtains the difference of frequency between the fundamental wave and a reference sound by means of analog operation so as to display it on a meter. However, the apparatus of this kind involves such problems that extra time and labor are necessary in order to convert the frequency deviation displayed on the meter into a cent value, and it is difficult to create the apparatus compact in size and to sufficiently enhance the measuring accuracy.